Combination expansible absorbent receptacle for investments



' May 27, 1941. c. E. SUMMY COMBINATION EXPANSIBLE ABSORBENT RECEPTACLEFOR INVESTMENTS Filed July 8, 1959 I yENTOR.- BY I @y O ATTORNfiPatented May 27, 1941 UNITED STATES TENT OFFICE COIWBINATION EXPANSIBLEABSOBBENT BEOEPTACLE FOR INVESTMENTS 4 Claims.

My invention pertains to a dental process and device.

An object of my invention is to provide an expansible arrangement forreceiving investments which will allow compensation for the contractionin size of gold inlays, in combination with suitable means for holdingsuch investments.

A further and important object of my invention is to provide a simpleabsorbing arrangement for absorbing the moisture from the investments sothat the investment liquid is removed to the greatest possible extent.

A further object of my invention is to provide an absorbing member whichincludes a certain means for rigidifying and bracing the investmentstructure.

A further object of my invention is to provide the above mentionedobjects in a structure of great simplicity, and which can bemanufactured at a very reasonable cost.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various parts of mydevice, whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out in my claims, and illustrated in theaccompanying drawing, in which:

Figure 1 is a sectional view taken through an investment with my form ofstructure used therewith,

Figure 2 is a sectional view taken along the lines 22 of Figure 1,

Figure 3 is a view of the absorbent and bracing strip, and

Figure 4 is an enlarged detail.

The principal objective contemplated in my invention is that ofproviding an investment with a lining engaging the outer boundariesthereof which will completely absorb the moisture from the investment ina convenient manner and in a minimum of time. Since the moisture must beremoved from the investment in order to provide the best type of fillingin dental inlays and the like, such means are important in the art. Myinvention also contemplates the provision of an interiorly positionedsupporting structure for the absorbent members so that when th absorbingmember is placed thereabout, a receptacle is provided for filling theinvestment into the necessary cavities.

I have used the character II] to represent a circular ring to which isattached at equally spaced intervals at II the vertically positionedbars I2 which bars extend upwardly and terminate in the slightlyinwardly inclined extremities I3. I have further used the character I4to represent a comparatively long strip of absorbent material such asasbestos, which has strong water absorbing characteristics and which canbe fireproof for the necessary purpose. The member I4 includes at oneend a series of perforations I5 which perforations extend substantiallythe width of the member I4, but which extend only to the approximatepoint I6 from the end I! of the member I4, the distance between the endI1 and the part I6 being substantially equal to the circumferentialdistance around the ring III or the bars I2, plus the diameter of thering In.

The arrangement is used in the following manner. The inlay supportingcone which is indicated by the character I8 is inserted within the ringI0 with the pin I9 being attached to the cone at 2!], and the usual waxshape 2I. The member I4 is then wrapped around the bars I2. However,before wrapping the member I4 about the bars I2, first a substantiallysquare portion approximately up to the point 22 (see Fig. 3) is torn offof'the strip, which portion is indicate-d by the character 23. Next, thestrip I4 is wrapped about the bars I2 starting at the point 22 so thatthe perforated portion of the strip will be directly adjacent to thesaid bars I2. The strip I4 is then wrapped about a consecutive number oftimes, forming two or three layers as indicated by the dotted structurein Figure 1. The investment material, which comprises the usualfireproof powder which is mixed with water, is then poured into thereceptacle provided by the strip I4 and the cone and will thencompletely surround the wax form 2I as shown in Figure 1. The smallsquare strip 2! which has been torn off is then placed at the top of theinvestment 'material and pressed downwardly slightly, occupying theposition as shown in'Figure 1. i

It should be noted that the investment material which is indicated bythe character 24 will flow through the perforations I5 along thecylindrical sides of the member I4 as well as the upper member 23. Theabsorbent material I4 will then completely absorb all of the moisturefrom the investment so that there will be no pockets formed at the mainbody of the investment and the perforated portions of the absorbentstrip will allow the moisture to travel through such perforations intothe outer layers of the strip. This complete absorption causes rapiddrying of the investment and after which the outer layers, as indicatedby the dotted lines in Figure 1, can be unwound and torn away,

leaving, however, the inner layer which includes the perforations l5. Asa result, after drying and hardening of the investment material, it willbe noted that the presence of the hardened portion of such material inthe perforations serve to support the entire cylindrical portion of thestrip I4 and to brace the entire unit solidly together with the uppermember 23 providing a firm outer cover.

In now referring to the bracing bars l2 again it will be noted that thebars l2 are movable radially from the center of the unit and which barsare adapted to compensate for the loss in volume of the gold inlay whichis to be formed in the impression 21 after the wax is removed by heat.In other words, after the gold is placed in the cone I8 and is thenmelted into the form 2| to form the inlay, the bars l2 will bendoutwardly from the center to compensate for the expansion necessary tooffset the loss of volume in the gold inlay itself when heated. If theinlays were formed in a solid cylindrical member, the expansion of themember itself would not take care of this discrepancy, but the barsbeing laterally movable, there will be a tendency to provide thisdesirable result. It will be understood that if desired the arrangementcan be filled with the investment by inverting the ring I 0 and placingthe portion 23 beneath the same and pressing the cone into the mass ofinvestment material; however, any arrangement can be used. The bendingof the bars I2 at l3 provides a more convenient manner of filling Whenthe arrangement is reversed, and the portion 23 of the absorbent stripI2 is smoothed around the peripheral boundaries of the arrangement toprovide a circular form.

If such is desired, the member M can be preformed into a cylindricalcavity with the perforate portion being inside as described, so that thecylindrical cavity can be made by the manufacturer and usable in thecylindrical form which can be then slipped over the bars l2. Thisarrangement will provide a cavity ready for use which will not be in thestrip form as shown in Figure 3. 7

It will now be seen that I have provided a process as well as anapparatus for removing moisture from investments which works incombination with an expansible arrangement, which expansible arrangementcompensates for the diminution in sizeof gold inlays when heated orformed, and it will be seen further that I have provided an absorbingmember which also acts as a bracing structure for an investment unit,and it will also be seen that I have provided a method of forming acompletely absorbing receptacle for investments, and that I haveprovided the above in a simple structure.

Some changes may be made in the construction and arrangement of theparts of my invention without departing from the real spirit and purposeof my invention, and it is my intention to cover by my claim anymodified forms of structure or use of mechanical equivalents which maybe reasonably included within their scope.

I claim as my invention:

1. A device for forming investments comprising a substantiallycylindrical open framework, a lengthened strip of highly absorbentmaterial adapted to be wound upon said framework, said strip having aplurality of spaced perforations at one end thereof to provide a singleply perforated investment receiving member, the further portions of saidstrip adapted to provide further absorbing plies, when said strip iswound continuously about said framework.

2. A device for forming investments comprising substantially cylindricalopen framework, a lengthened strip of highly absorbent material adaptedto be wound upon said framework, said strip having a plurality of spacedperforations at one end thereof to provide a single ply perforatedinvestment receiving member, the further portions of said strip adaptedto provide further absorbing plies, when said strip is woundcontinuously about said framework, said framework having free ends toprovide elasticity thereto for expansion purposes.

3. A device for forming investments comprising a substantiallycylindrical open framework, a lengthened strip of highly absorbentmaterial adapted to be wound upon said framework, said strip having aplurality of spaced perforations at one end thereof to provide a singleply perforated investment receiving member, the further portions of saidstrip adapted to provide further absorbing plies, when said strip iswound continuously about said framework, said framework having free endsto provide elasticity thereto for expansion purposes, the perforateportions of said strip being of a length substantially equal to thecircumference of said framework plus the diameter thereof to provide aperforate top covering member to the investment.

4. A device for forming investments compris ing a lengthened strip ofmoisture absorbing material, said strip being wound spirally to form acylinder to provide retainer means for plastic investment, said stripincluding a plurality of perforations in which said investment materialis adapted to flow to provide means for passage of moisture of saidinvestment material to the outer lining of said strip.

CHARLES E. SUMMY.

